Name: LUCAS RANGEL AFFONSO DE MIRANDA
Publication date: 08/11/2024
Examining board:
Name |
Role |
|---|---|
| GUILHERME BORGES PEREIRA | Examinador Externo |
| RICHARD DIEGO LEITE | Presidente |
| RODRIGO LEAL DE QUEIROZ THOMAZ DE AQUINO | Examinador Interno |
Summary: Transcranial direct current stimulation (tDCS) is a non-invasive technique that involves at least two electrodes: the anodal electrode (which depolarizes) and the cathodal electrode (which hyperpolarizes). With these two electrodes, improvements in performance can be observed after or during a single session of tDCS. However, there are gaps in the literature due to the heterogeneity of studies and the diverse applications of tDCS. In this context, the aim of the study was to investigate whether there is an effect of online tDCS on the performance of young men in a dynamic protocol for knee extensors and flexors using the isokinetic dynamometer. To address these questions, two studies were conducted. Article 1 aimed to explore the effect of tDCS on different brain regions to enhance performance in strength exercises and to identify practical application possibilities. Article 2 aimed to evaluate the effect of online tDCS on the motor cortex and prefrontal cortex in young men through measures of peak torque, average torque, fatigue index, time to peak torque, and rate of perceived effort using the isokinetic dynamometer. The sample consisted of 16 men (age = 24.44 ± 2.58 years; strength training duration = 5.50 ± 3.58 years). Six visits were conducted: Visit 1: familiarization. Visits 2 to 6 (randomized and crossover): online tDCS protocols, including tDCSP1 (2mA – motor cortex), tDCSP2 (2mA – prefrontal cortex), tDCSP3 (1mA – multifocal), control, and sham, with a 48 to 72-hour interval between visits. During the protocols, two dynamic sets were performed (Set 1: 10x60/s; Set 2: 40x120/s; with 3 minutes of rest between sets and limbs) on the dominant and non-dominant limbs for knee extension and flexion using the isokinetic dynamometer. Measures of peak torque, average torque, time to peak torque, fatigue index, and subjective effort perception were evaluated. No differences were observed between the protocols for peak torque, average torque, time to peak torque, fatigue index, and rate of perceived effort. Online tDCS applied to the motor cortex, prefrontal cortex, or multifocal regions does not improve the performance of young men in knee extension and flexion exercises.
Keywords: Transcranial direct current stimulation; muscle strength; physical performance; motor cortex; dorsolateral prefrontal cortex.
